code: def env_var(v: str) -> Tuple[str, str]:
      r = re.match(r"^([a-zA-Z_][a-zA-Z0-9_]*)=(.*)$", v)
      if r is None:
          raise ValueError(v)
      key, value = r.groups()
      return key, value
  
imports: import argparse
  import re
  import subprocess
  from typing import Dict, List, Optional, Tuple, Type
  from dstack._internal.cli.utils.common import console
  from dstack._internal.core.errors import ConfigurationError
  from dstack._internal.core.models.configurations import BaseConfiguration, BaseConfigurationWithPorts, ConfigurationType, DevEnvironmentConfiguration, PortMapping, ServiceConfiguration, TaskConfiguration
  from dstack._internal.utils.interpolator import VariablesInterpolator
label_desc: Use image node_id 1 for calling a global function with example usage: env_var(v) and returns: key,  value